Genetic organization of the car-I gene cluster (locus A), car-II gene cluster (locus B), fdxIfdrI locus (locus C), and fdrII locus (locus D) encompassing the pCAR3 genes involved in the degradation of carbazole by Sphingomonas sp. strain KA1. The genetic organization of the car gene cluster responsible for carbazole degradation in P. resinovorans CA10 is also shown. The carAa gene of CA10 is tandemly duplicated (36). The arrows in the physical maps indicate the size, location, and direction of transcription of the ORFs derived from the nucleotide sequence data.